Double inverted flares. (General)

Posted by PackardV8 On 2014/9/29 14:50:23

I've already tried googling with no results.
Here is the problem in question form:
Is there some rule or eng'ring concept or standard to indicate that the the tubing must be of DISsimilar material from the seat material???
Or to put it another way, Is it ok to mate steel tubing with double inverted flare to a steel seat in a fitting or casting etc. Steel to steel.

Can someone give an example of say a steel to steel or brass to brass etc.
I cn not recall any applications over the years where steel tubing with a double inverted flare ever mated to a steel item orr steel fitting. They are always dissimilar metals. No??